From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35781) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dwRx9-0000Op-Ii for qemu-devel@nongnu.org; Mon, 25 Sep 2017 07:53:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dwRx6-0004El-GI for qemu-devel@nongnu.org; Mon, 25 Sep 2017 07:53:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34194) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dwRx6-0004E6-7V for qemu-devel@nongnu.org; Mon, 25 Sep 2017 07:53:32 -0400 Date: Mon, 25 Sep 2017 13:53:16 +0200 From: Cornelia Huck Message-ID: <20170925135316.74fed6da.cohuck@redhat.com> In-Reply-To: <1506071794-4373-1-git-send-email-thuth@redhat.com> References: <1506071794-4373-1-git-send-email-thuth@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2] qdev: Mark devices as non-hotpluggable by default List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thomas Huth Cc: qemu-devel@nongnu.org, Igor Mammedov , Peter Maydell , Eduardo Habkost , Paolo Bonzini , Xiao Guangrong , "Michael S. Tsirkin" , Marcel Apfelbaum , Christian Borntraeger , Gerd Hoffmann , Stefano Stabellini , Anthony Perard , David Hildenbrand , David Gibson , Bharata B Rao , Amit Shah On Fri, 22 Sep 2017 11:16:34 +0200 Thomas Huth wrote: > Historically we've marked all devices as hotpluggable by default. However, > most devices are not hotpluggable, and you also need a HotplugHandler to > support these devices. So if the user tries to "device_add" or "device_del" > such a non-hotpluggable device during runtime, either nothing really usable > happens, or QEMU even crashes/aborts unexpectedly (see for example commit > 84ebd3e8c7d4fe955b - "Mark diag288 watchdog as non-hotpluggable"). > So let's change this dangerous default behaviour and mark the devices as > non-hotpluggable by default. Certain parent devices classes which are known > as hotpluggable (e.g. PCI, USB, etc.) are marked with "hotpluggable = true", > so that devices that are derived from these classes continue to work as > expected. > > Signed-off-by: Thomas Huth > --- > v2: Add missing devices and dropped "RFC" status. See Eduardo's reply on > the previous version of this patch for the rationale which devices need > to be hotpluggable: > https://lists.gnu.org/archive/html/qemu-devel/2017-09/msg06128.html > > hw/char/virtio-serial-bus.c | 1 + > hw/core/qdev.c | 10 ++++------ > hw/mem/nvdimm.c | 3 +++ > hw/mem/pc-dimm.c | 1 + > hw/pci/pci.c | 1 + > hw/ppc/spapr_cpu_core.c | 1 + > hw/s390x/ccw-device.c | 1 + > hw/scsi/scsi-bus.c | 1 + > hw/usb/bus.c | 1 + > hw/usb/dev-smartcard-reader.c | 1 + > hw/xen/xen_backend.c | 1 + > target/i386/cpu.c | 4 ++-- > target/s390x/cpu.c | 1 + > 13 files changed, 19 insertions(+), 8 deletions(-) Hm, this seems to break hotplug of virtio devices: (qemu) device_add virtio-net-pci,id=xxx Device 'virtio-net-device' does not support hotplugging (qemu) device_add virtio-net-ccw,id=yyy Device 'virtio-net-device' does not support hotplugging We probably need to enable hotplug for virtio devices as well?